/*
 * @BEGIN LICENSE
 *
 * Psi4: an open-source quantum chemistry software package
 *
 * Copyright (c) 2007-2024 The Psi4 Developers.
 *
 * The copyrights for code used from other parties are included in
 * the corresponding files.
 *
 * This file is part of Psi4.
 *
 * Psi4 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, version 3.
 *
 * Psi4 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along
 * with Psi4; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * @END LICENSE
 */

/*! \file
    \ingroup CCDENSITY
    \brief Calculates the one- and two-electron CC energies using the
    coresponding one- and two-particle density matrices.
*/
#include <cstdio>
#include <cstring>
#include "psi4/libdpd/dpd.h"
#include "MOInfo.h"
#include "Params.h"
#include "Frozen.h"
#define EXTERN
#include "globals.h"

namespace psi {
namespace ccdensity {

/* ENERGY_UHF(): Compute the UHF CC energy using the one- and two-particle
** density matrices.
*/

void energy_UHF(const struct RHO_Params& rho_params) {
    dpdfile2 D, F;
    dpdbuf4 G, A, B, C, DInts, E, FInts;
    double one_energy = 0.0, two_energy = 0.0, total_two_energy = 0.0;
    double this_energy, test_energy;

    outfile->Printf("\n\tEnergies re-computed from CC density:\n");
    outfile->Printf("\t-------------------------------------\n");

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 0, rho_params.DIJ_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 0, "fIJ");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDIJ = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 2, 2, rho_params.Dij_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 2, 2, "fij");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDij = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 1, 1, rho_params.DAB_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 1, 1, "fAB");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDAB = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 3, 3, rho_params.Dab_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 3, 3, "fab");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDab = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 1, rho_params.DIA_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 1, "fIA");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDIA = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 2, 3, rho_params.Dia_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 2, 3, "fia");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDia = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 0, 1, rho_params.DAI_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 0, 1, "fIA");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);

    /*    outfile->Printf( "\tDAI = %20.15f\n", this_energy); */
    one_energy += this_energy;

    global_dpd_->file2_init(&D, PSIF_CC_OEI, 0, 2, 3, rho_params.Dai_lbl);
    global_dpd_->file2_init(&F, PSIF_CC_OEI, 0, 2, 3, "fia");
    this_energy = global_dpd_->file2_dot(&D, &F);
    global_dpd_->file2_close(&F);
    global_dpd_->file2_close(&D);
    /*    outfile->Printf( "\tDai = %20.15f\n", this_energy); */
    one_energy += this_energy;

    outfile->Printf("\tOne-electron energy        = %20.15f\n", one_energy);

    if (params.onepdm) return;

    total_two_energy = 0.0;

    two_energy = 0.0;

    global_dpd_->buf4_init(&A, PSIF_CC_AINTS, 0, 2, 2, 0, 0, 1, "A <IJ|KL>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 2, 2, 2, 2, 0, "GIJKL");
    two_energy += global_dpd_->buf4_dot(&G, &A);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&A);

    global_dpd_->buf4_init(&A, PSIF_CC_AINTS, 0, 12, 12, 10, 10, 1, "A <ij|kl>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 12, 12, 12, 12, 0, "Gijkl");
    two_energy += global_dpd_->buf4_dot(&G, &A);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&A);

    global_dpd_->buf4_init(&A, PSIF_CC_AINTS, 0, 22, 22, 22, 22, 0, "A <Ij|Kl>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 22, 22, 22, 22, 0, "GIjKl");
    two_energy += global_dpd_->buf4_dot(&G, &A);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&A);

    total_two_energy += two_energy;
    outfile->Printf("\tIJKL energy                = %20.15f\n", two_energy);

    two_energy = 0.0;

    global_dpd_->buf4_init(&E, PSIF_CC_EINTS, 0, 2, 20, 2, 20, 0, "E <IJ||KA> (I>J,KA)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 2, 20, 2, 20, 0, "GIJKA");
    two_energy += global_dpd_->buf4_dot(&G, &E);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&E);

    global_dpd_->buf4_init(&E, PSIF_CC_EINTS, 0, 12, 30, 12, 30, 0, "E <ij||ka> (i>j,ka)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 12, 30, 12, 30, 0, "Gijka");
    two_energy += global_dpd_->buf4_dot(&G, &E);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&E);

    global_dpd_->buf4_init(&E, PSIF_CC_EINTS, 0, 22, 24, 22, 24, 0, "E <Ij|Ka>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 22, 24, 22, 24, 0, "GIjKa");
    two_energy += global_dpd_->buf4_dot(&G, &E);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&E);

    global_dpd_->buf4_init(&E, PSIF_CC_EINTS, 0, 23, 27, 23, 27, 0, "E <iJ|kA>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 23, 27, 23, 27, 0, "GiJkA");
    two_energy += global_dpd_->buf4_dot(&G, &E);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&E);

    two_energy *= 2;
    total_two_energy += two_energy;
    outfile->Printf("\tIJKA energy                = %20.15f\n", two_energy);

    two_energy = 0.0;

    global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 2, 7, 2, 7, 0, "D <IJ||AB> (I>J,A>B)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 2, 7, 2, 7, 0, "GIJAB");
    two_energy += global_dpd_->buf4_dot(&G, &DInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&DInts);

    global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 12, 17, 12, 17, 0, "D <ij||ab> (i>j,a>b)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 12, 17, 12, 17, 0, "Gijab");
    two_energy += global_dpd_->buf4_dot(&G, &DInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&DInts);

    global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 22, 28, 22, 28, 0, "D <Ij|Ab>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 22, 28, 22, 28, 0, "GIjAb");
    two_energy += global_dpd_->buf4_dot(&G, &DInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&DInts);

    two_energy *= 2;
    total_two_energy += two_energy;
    outfile->Printf("\tIJAB energy                = %20.15f\n", two_energy);

    /*
    ** Compute the Gibja contribution to the two-electron energy.  By
    ** spin-case this contribution looks like:
    **
    **  E(AA) <-- sum_IBJA G(IB,JA) <JA||IB>
    **  E(BB) <-- sum_ibja G(ib,ja) <ja||ib>
    **  E(AB) <-- sum_IbJa ( G(Ib,Ja) <Ja|Ib> + G(iB,jA) <jA|iB> -
    **                         G(Ib,jA) <jA|bI> - G(iB,Ja) <Ja|Bi> )
    **
    **  See Gibja.c for the definition of G here.
    */

    two_energy = 0.0;

    global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 20, 20, 20, 20, 0, "C <IA||JB>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 20, 20, 20, 20, 0, "GIBJA");
    two_energy += global_dpd_->buf4_dot(&G, &C);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&C);

    global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 30, 30, 30, 30, 0, "C <ia||jb>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 30, 30, 30, 30, 0, "Gibja");
    two_energy += global_dpd_->buf4_dot(&G, &C);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&C);

    global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 24, 24, 24, 24, 0, "C <Ia|Jb>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 24, 24, 24, 24, 0, "GIbJa");
    two_energy += global_dpd_->buf4_dot(&G, &C);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&C);

    global_dpd_->buf4_init(&C, PSIF_CC_CINTS, 0, 27, 27, 27, 27, 0, "C <iA|jB>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 27, 27, 27, 27, 0, "GiBjA");
    two_energy += global_dpd_->buf4_dot(&G, &C);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&C);

    global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 24, 27, 24, 27, 0, "D <Ij|Ab> (Ib,jA)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 24, 27, 24, 27, 0, "GIbjA");
    two_energy -= global_dpd_->buf4_dot(&G, &DInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&DInts);

    global_dpd_->buf4_init(&DInts, PSIF_CC_DINTS, 0, 27, 24, 27, 24, 0, "D <iJ|aB> (iB,Ja)");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 27, 24, 27, 24, 0, "GiBJa");
    two_energy -= global_dpd_->buf4_dot(&G, &DInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&DInts);

    total_two_energy += two_energy;
    outfile->Printf("\tIBJA energy                = %20.15f\n", two_energy);

    two_energy = 0.0;

    global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 21, 7, 21, 5, 1, "F <AI|BC>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 21, 7, 21, 7, 0, "GCIAB");
    two_energy += global_dpd_->buf4_dot(&G, &FInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&FInts);

    global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 31, 17, 31, 15, 1, "F <ai|bc>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 31, 17, 31, 17, 0, "Gciab");
    two_energy += global_dpd_->buf4_dot(&G, &FInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&FInts);

    global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 25, 29, 25, 29, 0, "F <aI|bC>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 25, 29, 25, 29, 0, "GcIaB");
    two_energy += global_dpd_->buf4_dot(&G, &FInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&FInts);

    global_dpd_->buf4_init(&FInts, PSIF_CC_FINTS, 0, 26, 28, 26, 28, 0, "F <Ai|Bc>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 26, 28, 26, 28, 0, "GCiAb");
    two_energy += global_dpd_->buf4_dot(&G, &FInts);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&FInts);

    two_energy *= 2;
    total_two_energy += two_energy;
    outfile->Printf("\tCIAB energy                = %20.15f\n", two_energy);

    two_energy = 0.0;

    global_dpd_->buf4_init(&B, PSIF_CC_BINTS, 0, 7, 7, 5, 5, 1, "B <AB|CD>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 7, 7, 7, 7, 0, "GABCD");
    two_energy += global_dpd_->buf4_dot(&G, &B);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&B);

    global_dpd_->buf4_init(&B, PSIF_CC_BINTS, 0, 17, 17, 15, 15, 1, "B <ab|cd>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 17, 17, 17, 17, 0, "Gabcd");
    two_energy += global_dpd_->buf4_dot(&G, &B);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&B);

    global_dpd_->buf4_init(&B, PSIF_CC_BINTS, 0, 28, 28, 28, 28, 0, "B <Ab|Cd>");
    global_dpd_->buf4_init(&G, PSIF_CC_GAMMA, 0, 28, 28, 28, 28, 0, "GAbCd");
    two_energy += global_dpd_->buf4_dot(&G, &B);
    global_dpd_->buf4_close(&G);
    global_dpd_->buf4_close(&B);

    total_two_energy += two_energy;
    outfile->Printf("\tABCD energy                = %20.15f\n", two_energy);

    outfile->Printf("\tTotal two-electron energy  = %20.15f\n", total_two_energy);
    if (params.ground) {
        outfile->Printf("\t%-7s correlation energy = %20.15f\n",
                        params.wfn == "CCSD_T" ? "CCSD(T)" : params.wfn.c_str(), one_energy + total_two_energy);
        outfile->Printf("\tTotal %-7s energy       = %20.15f\n",
                        params.wfn == "CCSD_T" ? "CCSD(T)" : params.wfn.c_str(),
                        one_energy + total_two_energy + moinfo.eref);
    } else {
        outfile->Printf("\tTotal EOM CCSD correlation energy        = %20.15f\n", one_energy + total_two_energy);
        outfile->Printf("\tCCSD correlation + EOM excitation energy = %20.15f\n", moinfo.ecc + params.cceom_energy);
        outfile->Printf("\tTotal EOM CCSD energy                    = %20.15f\n",
                        one_energy + total_two_energy + moinfo.eref);
    }
}

}  // namespace ccdensity
}  // namespace psi
